The Tech That Could Help Save Fukushima: Air Conditioning

We're running out of options here. Officials responsible for the Fukushima Dai-ichi nuclear power plant need to keep the reactors as cool as possible so as to control the amount of radiation being released by critical fuel rods that were damaged when, immediately after a 9.0-magnitude earthquake crippled the region and destroyed various water-pumping systems, temperatures shot up to over 1,000 degrees Centigrade. Today, the four reactors are fluctuating between 90 and 200 degrees, largely due to a near-constant stream of fresh water being pumped over them.

That water is heavily contaminated after passing over the reactors and huge concrete storage tanks located on-site are quickly filling up (hundreds and hundreds of tons of water). Officials can figure out a long-term containment plan later, but if they run out of storage then they'll have to stop pumping in water and temperatures will skyrocket. The solution? Air conditioning.

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The Japanese have decided to do what the French -- and others, though officials referenced the French specifically -- do: Use water chillers, essentially a form of high-power air conditioning, at Fukushima. "An envisioned air-cooling system would look like those already used in French nuclear plants," Hidehiko Nishiyama, spokesman and deputy director general of Japan's Nuclear and Industry Safety Agency, told the Wall Street Journal.

The chillers have never been used by the Japanese, according to the Japan Atomic Energy Institute, but it's time to pull all the stops. The Japanese have long relied on the nearby sea and its water to cool their reactors, but the underground water-pumping systems were destroyed by the tsunami that followed the 'quake. Water chillers might not work as well as the seawater used to, but it's a more practical solution -- and one that can be implemented quickly. The technology is there, and fairly basic; it's not much different from how home or office air conditioning units use the compression of a refrigerant such as Freon to absorb heat.

"Each reactor has two sets of water-pumping systems," the Journal explained. "The first runs water over radioactive fuel rods to keep them cool; that water then mostly evaporates as steam. The second cools that water so it can be used again. An air-cooling system would cool the water from the reactor, keeping it within the system."

The French have used this system for decades because many inland plants don't sit on a water source or are located next to a body of water that is insufficient. It takes a while to cool down after coming into contact with a nuclear reactor and even an entire lake can quickly overheat. A few years ago, NPR did a story about how hard it is for some reactors in France to operate during the summer. According to regulations, nuclear plants can't heat rivers or lakes above 82 degrees for fear of what it might do to the wildlife. With the sun shining and boiling water flowing from the pipes of a reactor, it's easy to hit that number.

In France, hitting that number is unwelcome, but it's not a debilitating problem. When the lake can no longer act as a repository for spent coolant, the plants employ a fleet of trucks to bring in extra supplies of cold water. Essentially, that's what Japan has been doing for over a month now. And there's no room left.